2,277 research outputs found
Affect Variability and Physical Health: The Moderating Role of Mean Affect
Research has only begun to explore how affect variability relates to physical health and has typically not assessed long-term associations nor considered the moderating role of mean affect. Therefore, we used data from the Midlife in the United States Study waves 2 (N = 1512) and 3 (N = 1499) to test how affect variability predicted concurrent and long-term physical health while also testing the moderating role of mean affect. Results indicated that greater negative affect variability was associated concurrently with a greater number of chronic conditions (p = .03) and longitudinally with worse self-rated physical health (p \u3c .01). Greater positive affect variability was associated concurrently with more chronic conditions (p \u3c .01) and medications (p \u3c .01) and longitudinally with worse self-rated physical health (p = .04). Further, mean negative affect played a moderating role such that at lower levels of mean negative affect, as affect variability increased, so did the number of concurrent chronic conditions (p \u3c .01) and medications (p = .03) and the likelihood of reporting worse long-term self-rated physical health (p \u3c .01). Thus, the role of mean affect should be considered when testing short- and long-term associations between affect variability and physical health
Nernst Effect and Superconducting Fluctuations in Zn-doped YBaCuO
We report the measurements of in-plane resistivity, Hall effect, and Nernst
effect in Zn doped YBaCuO epitaxial thin films grown
by pulsed laser deposition technique. The pseudogap temperature, ,
determined from the temperature dependence of resistivity, does not change
significantly with Zn doping. Meanwhile the onset temperature () of
anomalous Nernst signal above , which is interpreted as evidence for
vortex-like excitations, decreases sharply as the superconducting transition
temperature does. A significant decrease in the maximum of vortex
Nernst signal in mixed state is also observed, which is consistent with the
scenario that Zn impurities cause a decrease in the superfluid density and
therefore suppress the superconductivity. The phase diagram of ,
, and versus Zn content is presented and discussed.Comment: 6 pages, 5 figures, Latex; v2: to be published in PR
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Elucidating the Limit of Li Insertion into the Spinel Li4Ti5O12
In this work, we show that the well-known lithium-ion anode material, Li4Ti5O12, exhibits exceptionally high initial capacity of 310 mAh g-1 when it is discharged to 0.01 V. It maintains a reversible capacity of 230 mAh g-1, far exceeding the "theoretical" capacity of 175 mAh g-1 when this anode is lithiated to the composition Li7Ti5O12. Neutron diffraction analyses identify that additional Li reversibly enters into the Li7Ti5O12 to form Li8Ti5O12. density functional theory (DFT) calculations reveal the average potentials of the Li4Ti5O12 to Li7Ti5O12 step and the Li7Ti5O12 to Li8Ti5O12 step are 1.57 and 0.19 V, respectively, which are in excellent agreement with experimental results. Transmission electron microscopy (TEM) studies confirm that the irreversible capacity of Li4Ti5O12 during its first cycle originates from the formation of a solid electrolyte interface (SEI) layer. This work clarifies the fundamental lithiation mechanism of the Li4Ti5O12, when lithiated to 0.01 V vs Li
Superconductivity in the non-oxide Perovskite MgCNi3
The oxide perovskites are a large family of materials with many important
physical properties. Of particular interest has been the fact that this
structure type provides an excellent structural framework for the existence of
superconductivity. The high Tc copper oxides are the most famous examples of
superconducting perovskites, but there are many others [1]. Intermetallic
compounds have been the source of many superconducting materials in the past,
but they have been eclipsed in recent years by the perovskite oxides. The
recent discovery of superconductivity in MgB2 [2] suggests that intermetallic
compounds with simple structure types are worth serious reconsideration as
sources of new superconducting materials. Here we report the observation of
superconductivity at 8 K in the perovskite structure intermetallic compound
MgCNi3, linking what appear at first sight to be mutually exclusive classes of
superconducting materials. The observation of superconductivity in MgCNi3
indicates that MgB2 will not be the only one of its kind within the chemical
paradigm that it suggests for new superconducting materials
Large enhancement of the thermopower in NaCoO at high Na doping
Research on the oxide perovskites has uncovered electronic properties that
are strikingly enhanced compared with those in conventional metals. Examples
are the high critical temperatures of the cuprate superconductors and the
colossal magnetoresistance in the manganites. The conducting layered cobaltate
displays several interesting electronic phases as is varied
including water-induced superconductivity and an insulating state that is
destroyed by field. Initial measurements showed that, in the as-grown
composition, displays moderately large thermopower and
conductivity . However, the prospects for thermoelectric cooling
applications faded when the figure of merit was found to be small at this
composition (0.60.7). Here we report that, in the poorly-explored
high-doping region 0.75, undergoes an even steeper enhancement. At the
critical doping 0.85, (at 80 K) reaches values 40 times
larger than in the as-grown crystals. We discuss prospects for low-temperature
thermoelectric applications.Comment: 6 pages, 7 figure
Multi-sulfonated ligands on gold nanoparticles as virucidal antiviral for Dengue virus
Dengue virus (DENV) causes 390 million infections per year. Infections can be asymptomatic or range from mild fever to severe haemorrhagic fever and shock syndrome. Currently, no effective antivirals or safe universal vaccine is available. In the present work we tested different gold nanoparticles (AuNP) coated with ligands ω-terminated with sugars bearing multiple sulfonate groups. We aimed to identify compounds with antiviral properties due to irreversible (virucidal) rather than reversible (virustatic) inhibition. The ligands varied in length, in number of sulfonated groups as well as their spatial orientation induced by the sugar head groups. We identified two candidates, a glucose- and a lactose-based ligand showing a low EC50 (effective concentration that inhibit 50% of the viral activity) for DENV-2 inhibition, moderate toxicity and a virucidal effect in hepatocytes with titre reduction of Median Tissue Culture Infectious Dose log10TCID50 2.5 and 3.1. Molecular docking simulations complemented the experimental findings suggesting a molecular rationale behind the binding between sulfonated head groups and DENV-2 envelope protein
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